Method of expanding brake drums



April 9, 1935. J T NA 1,997,323

' METHOD OF EXPANDING BRAKE DRUMS Filed July 2, 1932 4 Sheets-Sheet l April 9, 1935. .1. F. STRNAD METHOD OF EXPANDING BRAKE DRUMS Filed July 2, 1932 4 Sheets-Sheet Id Y I rIII 9 I I I I III] II/IIIIIIIII/ April 9, 1935. J. F. STRNAD METHOD OF EXPANDING BRAKE DRUMS Filed July 2, 1932 4 Sheets-Sheet 4 ll ///////////l I 1 H1 |l I a M H W Patented Apr. 9, 1935 Lemnco Products, Inc., Bedfor'd, Ohio, a cor notation of Ohio 1' Application July 2,-'1932,'Sas1 N0. career 3'Claims. (0139 1522) This invention relates to a method of expanding automobile brake drums and the like. V

The principal object of the invention is to provide for suchexpansion with a much smaller size :5 machine than isre'quired when present-methods roughytreatment."

andequipment are employed. While. the following description "has special reference'to the expansion of brakedrums for the" purpose of inserting reinforcing wearringsgit will be understood that the invention is susceptible of being carried out 'for' the accomplishment of other purposes and-thatapparatus of different con struction can be employed for carryingout the process disclosed, V Afurther object of my invention is to provide for the'deformationof thevmetal ot' the brake drum in a plurality of easy stages whereby to reduce the chance ofweakening the metal-by too further object is the"provis ion"of a process which lends itselfto' performance bymechanism f the simplest construction 'andminimum num ber of working parts. V I

Other and morelimited: objects will beapparent from the following description when takenv in connection with 1 the accompanying drawings in which Fig. 1. .is a fragmentary sec tional View showingthe mechanism employed in connection with my improved process in the pcsition assumed just 'asfthe last stage is completed; Fig. "2 is: a section on theline 2-2 of Fig. l;-"Fig.{3- is a" section, through a brake drum showingjthe reinforcing wear ring in position; Figs j ifto Tinclusive are fragmentary sectional views indicating successive steps in the process 'showing the position of the parts and the operations performed; andfFigs. 8 .to ll inclusive are similar views showing a modified form of my improved process being .carriedL ut by theme of a slightly different apparatus'Fig. 11 indicating the completedproduct.

Referring now to the drawings, the apparatus will first be described. Thenumeral N! indicates. the lower end of the plunger of a power press,'

preferably a hydraulic press, which may be of conventional construction and is therefore not illustrated and II indicatesa fragment of the base thereof or any'fixed stationary member. Seated within a depression in the member II is a die ,member [2 of. annular form and conforming to the exterior of the brake drum in its 1 final shape. Attached to the plunger Ill by any suitable means not shown is a block carrying member l3 provided with a frusto conical downi V 10 inclusive is identicalwiththatjust described wardly extending projection l4 and internally threaded (openings l5 receiving a plurality headed studs l5. Receivedon the studs I6 :are

.sector shaped blocks i'l having inner. surfaces adapted. to engage the conicalcuter surface of the projection. is and provided with radially elongated openings i8. adapted to allow motion ofthe blocks ll radially withrespectitothe.pro

jection I l. ,The openings l8 are shouldered whereby to'allow aconsiderable verticalmotion of the blocks with respect to the member-13 axially of the studs i6, such. motion being lir'nited in a downward 'direction by the engagement of the head I6 with the inwardly extending flange l8 at the top of the block Ha.

It will be' observed that'the main.- portion :of theopening" it has a radial dimension'w'as much greater than the diameter of the he'ad. lfi as the radial motion of the block with respect-ito i v the projection [4 is intended to b'ei-Z'I'he smaller upper portion of the opening it bears the same relation to the shank of the stud I6. At the top and bottom of each of thebl'o cks I1. is acircular groove 19 of I -shaped cross section. Received in the grooves of all the blocksare splitirings 26 which urge the blocks inwardly into engagement with the projection ll." The sector shaped blocks II are, as is obvious from Fig; 2, slig htly spacedfrom each other and formaltogether substan-fl thirdoflwhich in the embodiment'shown in" Fig.1

is formed by a bevel Zl; 1 i i 1 It will be obvious that when the plunger 10 is drawn up from'the position shown in Fig; 1 that the blocks I! will ride downwardly with respect to the member 13 undertheinfl uence of gravity and theaction of the splitfrings 2fl -unti1'-;the head. of the stud l6; engages the flange-l Bathe blocks riding inwardly whereby to decrease the diameter of the surface defined by the. outer surfaces of the blocks. Obviously, when the blocks are thus in down position they can be inserted into a. brake drum or similar member of a diameter smaller than would accommodate them if they were in up" position with respect to the member I 3. It is also obvious that when the blocks are in down position and the plunger of 'the press is lowered, when the blocks are constrained against motion with the block holding member [3, they will begin to .'move radially under the wedging actionof the projection l4.

The outer surfaces define a gen outer surface of the blocks beingthus cylindrical from to to bottom. 7

In Fig. 4 I have shown the brake drum before any deformation has taken place and with the apparatus in the position assumed just as deformation is about to begin. It will be seen that the blocks I! are in down position with respect to the'member l3 and that most of the beveled portion of the blocks is within the flange 22 of the brake drum. These blocks are of such size that when the major part of the beveled portion is within the drum flange '22, it will engage such flange whereby to constrain downward movement of the blocks. Further downward movement of the member it" under the influence of the plunger It! will result in radial or expanding motion of the blocks. When the member 113 has been forced to full down'position, the parts will occupy the relations shown in Fig. 5;" Here it will be seen that approximately the upper third of the flange 22 is flared outwardly. The plunger is then moved upwardly and again lowered, the parts assuming the relation seen in Fig. 6 when the blocks II have entered the flange 22 touabout two thirdsits :depth, further downward motion of the blocks being prevented in thefsaine way as in the first stage. The plunger is-again brought down and the parts assume the relations seen in Fig. '1, the second third of the flange 22 being flared outwardly and the first third being operated upon by the cylindrical upper portion 7 of the block I! to impart thereto a, cylindrical shape: The plunger is again retracted and brought down, this time entering to the full depth of the flange and resulting in flaring the last third and imparting cylindrical shape to the upper two thirds as shown in Fig. 1. It is within v the contemplation of my invention to operate upon a drum'which has been shaped as shown in'Fig. l by a die having blockssuch as shown in Fig.8 whereby to impart cylindrical shape to the last or bottom third thereof. But this is not necessary since a ring 24 of the shape shown in Fig. 3 may be employed as well as one: of the shape shown at 25 in Fig. 1.1. 1

' While I prefer to carryvout my inventionin the steps just described, I may successfully employ blocks 26 not having the bevel 2| and constrain their downward'movement beyond the 'desired point by the use ofstops adapted to be engaged between-said blocks and some member fixed with respect to the drum flange 22. These stops may take the form of rings 21 and 230i difierentwidths for the difierent steps 'orsuitable projections may be formed on the blocks and engage some member fixed with respect to the die portion l2. In Fig. 8 I have shown the parts in the relation assumed just prior to deformation of the flrst zone of the flange 22,- the 101001926 except that the bevel portion 2! is omitted, the being engaged against the ring 21 for prevention of f urther downward-motion of the blocks a In Fig. 9 I have shown the position of the the ring 28 whereupon the parts will assume the.

relations shown in Fig. 10. The plunger is then 'forced fully down'resulting in imparting a cylindrical shape to the upper two thirds of the flange 22. The ring 28 is then'removed and the process repeated whereupon theflange 22- is shaped as sh'ownin Fig.'11. The" reinforcing and Wear ring 25 may then be inserted.

While I have shown and described preferred embodiments of my invention, I wish it understood that the sanie is not limited -to the de-.. tails shown and describedbut only in'accordance' flange for insertion of a reinforcing wear ring '7 expanding an outer annular portion of the braking flange of said drum by an initial stroke of said actuating element and then expanding an adjacent annular portion of said flange to the same diameter as saidflrst annular portion by a subsequent stroke of said actuating element;

JAMEs F. STRNAD. 

